These teachings relate generally to manufacturing objects/materials, and, more particularly, to digital manufacturing.
Most conventional manufacturing techniques can be considered analog since the conventional manufacturing techniques are practically continuous, their substructure cannot be arbitrarily specified and accuracies lost with each measurement and subsequent application.
Conventional three-dimensional printing processes are generally material-dependent and irreversible. Typically, conventional three-dimensional digital printers use continuous materials, with the digital specification being imposed by external logic. Conventional 3-dimensional fabrication is either additive or subtractive. Additive conventional three-dimensional printers work by depositing and/or bonding amorphous materials together in a way that results in a three-dimensional structure. Subtractive three-dimensional fabrication, such as with lathes or CNC milling machines, works by removing material from a block of bulk material. These techniques use complex control systems in order to precisely position the working tool in order to accurately build the desired object. The substrates, typically powders and binders for additive processes, or blocks of raw material for subtractive processes, define the material and surface properties of the final product, but not its shape.
Existing Freeform Fabrication is mainly Analog Additive 3D Printing, as most existing assemblers build structures by dispensing small amounts of one or two different materials as droplets of very precise size and in very precise location. Most existing commercial free-form fabrication printers build by putting together small quantities of no more than a few expensive materials. In order to make high-resolution objects, they need to be very precise, and therefore they cost between tens and hundreds of thousands of dollars and must be operated by skilled technicians.
Existing technology in this field typically employs one of several processes. In one method, a component is constructed by depositing a first layer of a fluent porous material or porous solid. Next, a binder material is deposited to selected regions to produce a layer of material. A second method consists of incorporating a movable dispensing head provided with a supply of material which solidifies at a predetermined temperature or when exposed to light or UV light. Instead of dispensing drops, other apparatuses place a filament at the desired position then heat it to convert a portion of the filament to a flowable fluid that is solidified in that position. A third approach comprises fabricating a three-dimensional object from individual layers of fabrication material having a predetermined configuration. Successive layers are stacked in a predetermined sequence and fixed together to form the object. Refinements include producing parts from two distinct classes of materials, where the first class of material forms a three-dimensional shape defined by the interface of the first class of material and the second class of material.
Recent manufacturing techniques such as bottom-up self assembly offer some of the benefits of digital matter in their ability to spontaneously assemble materials guided by local interactions between components; however, self-assembled processes can be difficult to control and are generally limited to regular, semi-periodic or random structures. Top-down deterministic pick-and-place approaches offer precise control over production and are useful where a small number of components are assembled in specific ways. However, top-down methods of assembly are limited in their throughput and at small scales are often limited to two dimensions. Attempts have been made to reconcile different modes of assembly such as hierarchical, directed, and templated self assembly. Recent rapid-prototyping technologies based on selective curing have opened the door to top-down fabrication of arbitrarily complex geometries, but cannot handle prefabricated building blocks; as a result, they are limited to a small set of homogeneous materials with mutually compatible rheological properties.
A digital assembler for creating three-dimensional objects from digital materials where a new line is fed to the assembly head and added to the structure has been described but such a technique is limited in its throughput. There is a need for a digital manufacturing system capable of faster throughput and capable of scale up while still obtaining an accurate output.